Printer slotter roller adjustment



M. E. GREENWOOD PRINTER SLOTTER ROLLER ADJUSTMENT l Filed Aug. 23, 1955 2 Shets-Sheet l MMA/,7 AZN/WMZ.

IH. E. GIWEENWD PRINTER SLOTTER ROLLER ADJUSTMENT Filed Aug. 2 5. 1955 2 Sheets-Sheet 3 jf V ATTORNEYS.

' the same number of teeth.

United States Patent O PRINTER SLOTTER ROLLER ADJUSTMENT Henry B. Greenwood, Baltimore, Md.

Application August 23, 1955, Serial No. 530,031

5 Claims. (Cl. 101-248) This invention relates to printer slotters used for printing and slotting carton blanks, and, more particularly, to `an improvement in the roller shaft adjustments of printer slotters. Boxes and similar products made from blanks passing through these machines are usually fitted with corrugated board of various thicknesses. It is, consequently, necessary to provide an adjustment of the pressure rollers to accommodate them to different thicknesses of board. Conventionally an external gear is mounted on one roller shaft to connect this gear with an internal gear mounted on the shaft of the other roller, the two gears having In order for a coupling of this sort to operate satisfactorily, however, the shafts must be aligned as accurately as possible. Since the rollers of printer slotters are adjusted transversely, coupling-s of the external and internal gear type have been found unsuitable. It has, consequently, been the practice in the industry to support the bearings of the rollers in sliding blocks which ride in slots in the frame. However, this slotting of the frame is undesirable 'because it materially weakens the support for the rollers. The remaining portion of the frame must, consequently, be excessively thick in order to give adequate strength to resist the stresses. Even then, failure due to roller pressure and vibration cannot always be avoided. Another alternative heretofore employed has been eccentric adjustment wherein one roller, together with its driving gear, has been moved eccentrically relative to the other. Again, difficulty has been encountered with this arrangement due to the shifting of the line of contact and to the irritating noise which inevitably accompanies the adjustment.

While still other printer slotters in the past have attempted to provide for the movement of the rollers in the adjustment of the machine `to different thicknesses of material and have avoided the slotting of the frame and shifting of gears relative to each other, these constructions have been disadvantageous in that a separate support for the gears connecting the pressure rollers has been necessary, thus greatly increasing the width of the machine and increasing the number of parts. Moreover, a tendency to failure and change of the Contact line or pitch line of the intermeshing gears has been noted.

It is, accordingly, one object of the present invention to provide an improved adjustment of the roller shafts in a printer slotter so that the printer slotter will operate satisfactorily despite substantial misalignment of the shafts.

Another object of this invention is to provide an improved adjustment of the roller shafts in a printer slotter whereby additional outside support for the gears is eliminated, thus greatly simplifying the construction and reducing the overall width of the machine without reducing the length of the rollers or the capacity of the ma chine.

Yet another object of the present invention is to provide an improved adjustment of the roller shafts in a printer slotter to accommodate the machine to varying thicknesses of material.

A further object of the present invention is to provide an improved adjustment of the roller shafts in a printer slotter which is comparatively simple and inexpensive to manufacture, and is capable of transmitting a large torque between misaligned shafts.

The present invention further provides for the adjustment of both ends of each roller uniformly and simultaneously. The gears are kept permanently in perfect mesh so that they always turn on a true pitch line without danger of back lash or lost motion. A uniform angular relation between the rollers and the driving gears is maintained, even though the rollers are shifted relative to these gears in making the adjustment. In this way uniform speed of the drive and uniform angular speed of the rollers are maintained.

Other objects, features, and advantages will be apparent from the specification read in conjunction with the following figures, in which:

Figure l is a vertical section through the axis of one pair of pressure rollers, showing the rollers in elevation and the bearings and adjustment features in section;

Figure 2 is a partial, enlarged sectional view of the adjusting coupling whereby the gears are meshed; and

Figure 3 is a cross section taken along the line 3 3 of Figure 2.

Referring now to the drawings in greater detail, it will be readily apparent that each numeral is used to indicate the same or similar parts in the different figures. As shown in the figures, the apparatus comprises essentially right and left side frames 11 and 12, respectively, upper pull roller 13 mounted on rotatable shaft 14, and lower pull roller 15 mounted on shaft 16. At 52 shaft 14 is secured in its position by stop collars 50 and 51, each of which is provided with a set screw, 61 and 62 respectively. Lubrication is provided for shaft 14 at 49 and 63. The shaft 14 has keyed thereto the gear 17. It Will be appreciated that gear 17 may be driven by the printer cylinder gear. Teeth 45 of gear 17 mesh with external teeth 46 of gear 18. Gear 18 has, in turn, a driving connection to the shaft 16 of roller 15, which will be described in greater detail.

In the apparatus as shown, the shaft 14 of the upper roller 13 is mounted in suitable roller bearings 19 and 20 in the side frames 11 and 12.

Shaft 16 of lower roller 15 is set within bearings 21 and 22, which are, in turn, fixed within the carrier designated generally at 23 and 24. This carrier fits into slots of the main frame at 25 and 26. By mounting the shaft 16 in this way, rotation of the shaft within its 'bearings as well as vertical movement of the shaft within the slot in the side frames, is made possible.

The carrier 23 and 24, supported within the slots at 25 and 26, may be vertically adjusted by any suitable means. In the apparatus shown, crank 27 is fixedly secured to adjusting shaft 28. As will be evident, adjusting shaft 28 projects through apertures 53 and 54 in side frames 11 and 12 and is secured in its position by stop collars 55 and 56, each of which is provided with a set screw, designated at 57 and 58. Shaft 28 is keyed at 29 to pinion 30, which meshes with pinion 31 of vertical shaft 32. Pinion 31 is keyed to vertical shaft 32 at 59. Vertical shaft 32 is xedly secured to base 12 by screw 33 and is provided with a bearing at 34 and a flange designated generally at 35. The portion of the vertical shaft designated at 36 is screw-threaded and is operatively associated with the carrier 24 through connecting element 60. When the adjusting shaft 28 is rotated by crank 27 pinion 30, meshing with pinion 31, causes the shaft 32 to rotate. Since shaft 32 is not movable axially, the movement of .vertical shaft 32 causes vertical movement of carrier 24.

Patented Apr. 29, 1958` Though the vertical adjustment of the roller has been discussed with reference only to the elements associated with the left side frame, it will be readily recognized that the vertical adjustment of the roller 15 brought about through vertical shafts gives a uniform and equal adjustment of both ends 23 and 24 of the carrier, thus maintaining a uniform grip of the roller throughout its length. On account of the relative positioning of the bevel gears and 31 in the particular embodiment illustrated, the threads on the upper ends of the shafts 32 must obviously be of opposite hand.

Shaft 16 of roller 15 is bolted at one end by washer 37 and fits within collar 38, to which it is keyed at 39. The washer 37 prevents the slipping of key 39. Collar gear 38 is provided with internal teeth 40, which mesh with the external teeth 41 of wobble pin 42. Wobble pin 42 is also provided with external teeth at 43, which mesh with teeth 44 of gear 18. As will be readily apparent, driving gear 17 meshes with teeth 46 of gear 18. The stub shaft designated generally at 47, together with ball bearings designated at 48, serves to support gear 18. It should be noted that the area occupied by the supporting structure is significantly less than that found in any prior apparatus of this type. This is, to a large extent, due to the fact that the wobble pin is virtually totally inclosed within gear 18 and collar gear 38.

When roller 15 is moved vertically, wobble pin 42 will move angularly, but the external teeth 41 and 43 will continue to mesh with internal teeth 40 of collar gear 38 and internal teeth 44 of gear 18, respectively. Thus, driving torque is transmitted to the wobble pin 42 through meshing with external teeth 44 of gear 18, and transferred to the shaft 16 through internal teeth 40 of collar gear 38. As indicated in Figure 3, a slight clearance is preferably allowed between external teeth 41 of wobble pin 42 and internal teeth 40 of collar gear 38. It is also preferred that a slight clearance be maintained between external teeth 43 of the wobble pin and internal teeth 44 of gear 18 so that these parts need not be made to precise dimensions.

Since the roller 15 is adjustable vertically, the wobble pin must be capable of operating satisfactorily despite misalignment. This is made possible, in part, by the shape of the external teeth of the wobble pin within the internal-external gear. As shown most clearly at 64 in Figure 2, the pitch surfaces of the external teeth of the wobble pin are made outwardly convex. Moreover, the spaces between the teeth are substantially uniform in shape and size throughout their length, as shown in Figure 3. It will also be apparent that the thickness of the teeth decreases in a radially outward direction, giving the teeth a tapered shape which is accentuated by the fact that the teeth spaces are substantially uniform in width rather than tapered. Because of the construction of the wobble pin housed within the internal-external gear, an angular position is made possible which avoids binding the gear teeth when the roller shaft is vertically adjusted. In other words, it has been found that the external 4teeth of wobble pin 42 will continue to mesh with driving gear 18 at one end and connecting collar gear 38 at its other end when its axis is at an angle with both the roller 15 and the driving gear 18. It is important to note that as the roller 15 moves vertically to accommodate corrugated board of different thicknesses, the position of the driving gear 18 is not altered. It should also be noted that the angular relation between the roller 15 and the gear 18 is constant and there is no relative angular shifting of the roller due to vertical adjustment.

Employing the wobble pin within the internal-external gear as described prevents clogging of the gears and makes possible the employment of a frame of relatively reduced weight. Among other important advantages gained from the use of this invention are increased compactness, simplicity, economy in maintenance and operation, and increased eiciency.

Having thus described specifically and in detail a single embodiment of this invention in order that the manner of constructing and operating the same may be fully disclosed, it is to be understood that the specific terms herein are used descriptively rather than in a limiting sense, and that the construction is capable of considerable variation in its application without departing from the spirit of the invention.

Having thus described this invention, what is claimed as new and desired to be secured by Letters Patent is:

l. In Ia printer slotter, a pair of co-operating rollers -mounted on rotatable shafts, said rollers adapted to en- Igage the opposite sides of a sheet to advance said sheet by gripping pressure, means whereby the first roller and shaft are mounted in adjustment and are adjusted toward and from the second roller and shaft, a drive gear keyed to said second roller shaft, and means for providing an axially variable driving connection between said driving gear and said first roller shaft, said means comprising a collar gear keyed to said first roller shaft and provided ywith internal teeth, coaxially disposed interconnected in ternal and external annular gears rotatably subjected in general axial alignment with said collar gear, said external gear being in driven engagement with said driving gear, and a wobble pin extending axially through said external gear and provided at its opposite ends with external teeth, said teeth at the opposite ends of the wobble pin respectively being received in and meshing loosely with the respective internal gear and the internal teeth of the said collar gear, the pitch surface of said wobble pin teeth being spherical, whereby the said wobble pin may transmit drive torque between said gears despite relative axial misalignment of said last mentioned gears.

2. In a printer slotter, a frame, first and second cooperating rollers rotatably subjected in said frame, means for adjusting the first said roller toward and away from the second said roller, a first internal gear `co-axially fixed to the first said roller, a second internal gear rotatably subjected on said frame for rotation about a fixed axis, said second internal gear being axially spaced from said first internal gear, an annular external gear fixed co-axially to said second internal gear in the axial space between said first and second internal gears, a coupling shaft extending through said annular gear and having external gears at its opposite ends, the teeth of said external gears having spherical pitch surfaces, said `teeth being received in and loosely meshing with the respective internal gears, said internal gears and said annular gear jointly providing a housing for said coupling shaft, clearance being provided between coupling shaft and :said annular gear to permit said adjustment of the iirst roller, and a drive gear co-axially fixed to said second roller in driving engagement with said annular gear to correlate the rotational yspeeds of the respective rollers in all positions of adjustment of said first roller.

3. In a printer slotter, a frame, first and second cooperating rollers rotatably subjected in said frame, means for adjusting the first said roller toward and away from the second said roller, a first internal gear `co-axially fixed to the first said roller, a second internal gear rotatably subjected on ysaid frame for rotation about a fixed axis, said second internal gear being axially spaced from said first internal gear, an annular external gear fixed coaxially to said second internal gear in the axial space between said first and second internal gears, a coupling shaft extending through said annular gear and having external gears at its opposite ends, the teeth of said external gears having spherical pitch surfaces, said teeth being received in and loosely meshing with the respective internal gears, said internal gears and said annular gear jointly providing a housing for said coupling shaft, clearance being provided between `coupling shaft and said annular gear to permit said adjustment of the first roller, and gear means in driving relation with said annular gear.

4. In a printer slotter, a frame, rst and second cooperating rollers rotatably subjected in said frame, means for adjusting the lirst said roller toward and away from the said second roller, a driven element subjected on said frame for rotation about a rst axis and spaced axially from said rst roller, an annular external gear ixed coaxially to said driven element between said driven element and the said roller a coupling shaft extending through said annular gear and universally connected at its opposite ends to 'said element and to said first roller respectively to transmit rotation therebetween, clearance being provided between said .coupling :shaft and said annular gear to permit said adjustment of the rst roller, and a drive gear co-axially fixed to said second roller in driving engagement with said annular gear to correlate the rotational speeds of the respective rollers.

5. The combination of claim 2, wherein said roller gear is integrally connected to said second internal gear.

References Cited in the fille of this patent UNITED STATES PATENTS 2,191,988 Greenwood Feb. 27, 1940 2,425,167 Whitehead Aug. 5, 1947 2,444,547 Whitehead July 6, 1948 FOREIGN PATENTS 649,408 Great Britain Jan. 24, 1951 699,420 Great -Britain Nov. 4, 1953 

